<!DOCTYPE html>
<html>
	<head>
		<meta charset="UTF-8">
		<meta name="viewport" content="width=device-width, initial-scale=1.0, user-scalable=no, minimum-scale=1.0, maximum-scale=5.0" charset="UTF-8">
		<meta name="apple-mobile-web-app-capable" content="yes">
		<meta name="apple-mobile-web-app-status-bar-style" content="black">
		<meta name="format-detection" content="telephone=no">
		<title></title>
		
		<style> 
			 body{width:100%;height: 100%;margin:0;padding:0;box-sizing:border-box;}  
			  .aa{width:100%; height:5rem; border:1px solid #000000; float:left;}     
			  .bDiv {background:green;width:100px; height:20px; margin-top:10px;}        
			  .cDiv {background:black; position:relative; width:100px; height:20px;} 
		</style>
	</head>
	<body>
		<!--就是外层DIV设置了高与宽，内层DIV如果设置maring-top不起作用（FIREFOX和IE8中测试），原因大致是内层div没有获得layout。如下面的代码：-->
		<div class="aa"> 1111
    		<div class="bDiv">bdiv</div>     
			<div class="cDiv">cdiv</div>
			 
		</div>
	</body>
</html>
